Crystal holder assembly



July 1, 1947. s. A. BOKOVOY ETAL CRYSTAL HOLDER ASSEMBLY Filed Sept. 18, 1944 I N V EN TORS 50K 7 GARE/30A J/IMUEZ I4. Kf/VTO/V A. BY $4 I v ATTORNEY Patented July 1, 1947 2,423,08L CRYSTAL HOLDER ASSEMBLY Samuel Alexander Bokovoy,

East Orange,

Kitch Garrison,

Verona, and Kenton N. J., assignors to Federal Telephone and Radio Corporation, New York, N. Y., a corporation of Delaware Application September 18, 1944, Serial No. 554,662

The present invention relates to frequency determining unit assemblies for crystal controlled oscillator circuits and has for its object to provide an improved housing and supporting construction for a piezo-electric crystal element of simplified and compact design. Advantages thereof incident to the improved design and arrangement include greater ease and also econonly in manufacturing and a structural arrangement offering the maximum protection to the crystal and mounting parts from atmospheric or other disturbances together with added security against displacement of the crystal element.

It further incorporates therein an advanced type of resilient contact mounting of the crystal. The latter is designed particularly to effeet a material reduction in the undesired mechanical damping of the crystal vibration by the provision of a mounting support of a type providing maximum freedom of crystal movement. The several features thereof moreover are embodied in a manner to contribute to the compactness of the structural unit thus better adapting it for the plug-in pin terminal type of structure for use with equipment of limited space and weight requirements such as radio sets of aircraft and the like.

The foregoin and other features and advantages of the present invention will be more fully understood by reference to the accompanying drawing wherein like reference characters are applied to the corresponding parts in the several views.

In the drawings:

Fig. l is a view the major portion of which is a central vertical section taken parallel to the face of the crystal and showing the latter and the lower portion in side elevation.

Fig. 2 is a cross sectional view thereof taken on line 22 of F18. 1.

Fig. 3 is a plan view of the base portion and contact members mounted thereon.

Fig. 4 is a sectional view to the housing cover member taken on line 4-4 of Fig. 1.

In the preferred embodiment of the invention as here shown the features thereof are incorporated in a resonator unit of the bottom end loading type having a base portion provided with terminal plugs or pins and with contact members rigidly mounted thereon and wherein the socket or enclosure for the crystal element is formed within a housing or cover member secured to the base and having a bottom opening for the reception of the crystal.

The base portion of the crystal holder is in- 8 Claims. (Cl. 171-327) dicated at I formed of insulating plastic material molded to embed and secure therein the terminal pins 2 provided with knurled portions 3 for mechanical bonding and having upper extensions 4 projecting slightly above the plastic body. The base as shown is of generally rectangular form having a marginal recess 5 providing outwardly directed shoulders 8 designed for the reception of the lower marginal flange extension I oi the plastic cover member 8. This housing or cover member 8 is formed with an internal socket or chamber 9 open at its bottom end and providing for the reception of the crystal or resonant element indicated at In. Tile chamber or socket 9 is of a size with relation to the crystal to permit of its reception in close but spaced relation to its sidewalls and at its upper end is formed with downwardly and inwardly extending spaced shoulders H of a form go providing an under surface of inverted V for mation to provide a seat or bearing, for the upper end of the crystal, of limited or reduced con-- tact area.

The resonator or crystal element [0 is of special 2:; formation having tapered or beveled upper and lower marginal end portions i2 and is provided with the customary opposite face platin electrodes i3 which are extended over the beveled portions with-the required spacing for electrical separation. For cooperation therewith in completing the electrical connection and likewise retaining the crystal element in its position but with a minimumof damping eilfect upon its vibration, there is provided an improved form and arrangement of spring contacts. These contact members are'shown at It formed of stamped flat spring metal in angular configuration having inwardly extending arm portions it cut out to closely receive the projected ends of the terminal pin extensions 4 to which they are secured by a weld or solder connection. At their inner ends the contact members H are formed with oppositely and inwardly extending contacting lip portions it which are bent downwardly, into reversely inclined and spaced relation, to provide a resilient contact bearing for the lower end of the crystal of general V formation. For the purpose of affording rigid support to the seating end portions of the contacts, supporting posts or pins ll are embedded in the base material to project therefrom in an arrangement centrally and outwardly of the lip portions and the ends thereof and are soldered or welded as shown to the contact member ll, the outer margins of which are recessed for the reception of the pin ends. As

best shown in Fig. 2 the base portion on its upper surface and centrally thereof is provided with a recess I8 for the reception of the contact lips and end portion of the crystal.

- The angularity of the beveled upper and lower ends of the crystal is such as to be more acute than the angularity f the walls of the shoulders H and likewise the angularit of the contact lips I6. From this arrangement it follows that the point, or line, of contact engagement between the supporting members and the end of the crystal is confined to limited areas and which moreover is inwardly of the'opposite faces of the crystal. In consequence of this desirable arrangement, as will be readily understood, there is a minimum or negligible damping effect upon the natural vibration of the crystal element.

As will be resognized from the structural arrangement and relation of the parts the proper assembling of the crystal is facilitated by its simple insertion within the cover member and the subsequent assembling of the base therewithin which operation the projecting end of the crystal is engaged by the inclined lip portion 16 in a manner to constrain the proper positioning thereof. As is customary a resilient sealing washer I8 is interposed between the base and cover upon assembling and securing screws 20 are provided fitting apertures in the base and threading into the cover member. In the improved structure as illustrated and for furthering the degree of compactness obtained thereby the securing screws are positioned in an angular relation and intermediately positioned. This is permitted by the provision of inward boss ex-- tensions 2| of the cover member partially oncroachin upon the socket or chamber and aligned inward bosses 22 formed by an inwardly widening of the sidewall of the base portion 1.

The improved resonator .unit structure a disclosed attains compactness to a maximum degree While afiording improved resilient contact support for the crystal of particularly secure and durable construction. As will be noted in the latter connection, the flat contact members have extended bearing support on the flattened upper surface of the base and are rigidly secured against deflection and displacement by soldering to the terminal pin portions -l and to the post I! in a manner giving good support thereto and to preserve the proper position of the contact lips H5. The improved arrangement as will be noted from Fig. 1 provides for not only a limited area contact with the crystal but a desirable three point engagement therewith as aiforded by the lugs l l and contact lip engagement in a manner insuring against angular displacement of the crystal with minimum of engagement therewith.

In addition to having a minimum restrictive influence on the vibration of the crystal the improved resilient contact support thereof provides for a desirable range of self adjustmentto accommodate for variations in production tolerances and the contact arrangement is of a character to materially reduce wear or scratching of the electrodes upon repeated assembling.

The function of the base and of the cover can easily be exchanged by providing the resilient support of the base in the cover member and the shoulders I I, shown now in the cover, in the base member.

While there is disclosed a. desirable embodiment of the features of the invention it will be understood that varied modifications may be made therein without departing from the scope of the invention as defined in the appended claims.

What is claimed is:

1. A frequency determinin unit of the character described comprising separable base and cover members of insulating material, said cover member having a bottom opening socket for the reception of a crystal element and formed with spaced angular supports for the crystal at the inner end thereof, terminal pins and contacts connected to the pins supported by the base member, said contacts consisting of fiat metal having angularly deflected contact lip portions in cooperating spaced relation to provide a central resilient V bearing for a crystal and a crystal element provided with opposite face electrodes positioned to have bearing engagement with the cover angular support and with the resilient contact bearing.

2. A frequency determining unit of the character described comprising separable base and cover members of insulating material, said cover member havin a bottom opening socket for the reception of a crystal element and formed-with spaced angular supports for the crystal at the inner end thereof, terminal pins and contacts connected to the pins supported by the base member, said contacts consisting of flat metal having angularly deflected contact lip portions in cooperating spaced relation to provide a central resilient V bearing for a crystal and a, crystal element provided with opposite face electrodes and having beveled upper and lower ends and having bearing engagement with the cover angular support and with the resilient contact bearing.

3. A frequency determining unit of the character described comprising separable base and cover members of insulating material, said cover member having a bottom opening socket for the reception of a crystal element and formed with spaced supports for the crystal at the inner end thereof and provided with angular lower surfaces, terminal pins secured in the base, contacts connected to the pins on the upper side of the base member, said contacts consisting of flat metal having angularly and downwardly deflected contact lip portions in cooperating spaced relation to provide a central resilient V bearing for a crystal, anchor studs secured in the base and to the contacts adjacent the lip portions thereof and-a crystal element provided with opposite face electrodes having bearing engagement with the cover angular supports and with the resilient contact bearing.

4. A frequency. determining unit of the character described comprising separable rectangular base and cover members of insulating material; said cover member having a bottom opening socket for the reception of a crystal element and formed with two outwardly spaced supports for the crystal at the inner end thereof, terminal pins and contacts secured in the base connected to the pins and bearing on the upper surface of the base member, said contacts consisting of flat metal having angularly and downwardly deflected contact lip portions in cooperating spaced relation to provide a central resilient V bearing for a crystal, anchor studs secured in the base and 5. A frequency determining unit consisting of a holder comprising separable base and cover members of insulating material, said cover member having a bottom opening socket for the reception of a crystal element and formed with angular supports for the crystal positioned at each side of the central axis of the holderfterminal pins and contacts connected thereto supported by the base member, said contacts consisting of flat metal having angularly and downwardly deflected contact lip portions in cooperating spaced relation to provide a central resilient Y bearing for a crystal and a crystal element provided with opposite face electrodes having bearing engagement with the cover angular supports and with the resilient contact bearing to provide three point supporting engagement with the crystal.

6. A frequency determining unit comprising a holder consisting of separable rectangular base and cover members of insulating material, said cover member having a bottom opening socket for the reception of a crystal element and having inverted V supports for the crystal at the inner end of the socket and at opposite .sides of its central axis, terminal pins secured to the base. contacts connected to the pins and bearing on the upper surface of the base member, said contacts being of flat metal having angularly and downwardly deflected contact lip portions in cooperating spaced relation to provide a central resilient V bearing for a crystal, anchor studs connected to the contacts and embedded in the base, a crystal element and associated electrodes positioned for bearing engagement with the cover supports and with the resilient contact bearing and means to secure the base and cover members together.

7. A frequency determining unit comprising a holder consisting of separable base and cover members of insulating material, said cover member having a bottom opening socket for the reception of a crystal element and formed for supporting engagement with the crystal at the inner end thereof, terminal pins .and contacts supported by the base member, said contacts consisting of flat metal having angularly and downwardly deflected contact lip portions in cooperating spaced relation to provide a contact resilient V bearin for the crystal and a crystal element and associated electrodes positioned to have bearing engagement with the cover sup- 1 port and with the resilient contact bearing.

8. A frequency determining unit having a housing composed of separable base and cover members of insulating material, one of said members having a socket for the reception of a crystal element, terminal pin and contacts connected to the pins supported by said one of the members, said contacts consisting or flat metal having angularly deflected contact lip portions in cooperating spaced relation to provide a central resilient v bearing for the crystal and the other of said members being provided with spaced angular supports providing an opposite bearing for the crystal and a crystal element provided with 0D- posite face electrodes positioned to have bearing engagement with the angular supports and with the resilient contact bearing.

SAMUEL ALEXANDER BOKOVOY. KENTON KITCH GARRISON.

REFERENCES CITED UNITED STATES PATENTS Name Date Bokovoy Nov. 14, 1944 Number 

